Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Emag Integration problem! HELP!

  1. May 18, 2010 #1
    Now then, im close to shedding a tear with this one.

    This integral has been popping up in a few electromag examples iv been doing and i have absolutely no idea whats going on here.

    The integral is 1/[(x2+z2)3/2] with respect to x

    According to the textbook the answer is x/[z2(x2+z2)1/2]

    I initially, without evening really thinking, went straight for -1/(x[x2+z2]1/2)

    Any ideas?
    Thanks
     
    Last edited: May 18, 2010
  2. jcsd
  3. May 18, 2010 #2
    First of all, try to find the partial derivative with respect to x (treating z as a constant parameter) of the textbook's answer. If it gives your integrand, then it is correct. If not, it is wrong.
     
  4. May 18, 2010 #3
    Iv used a computer, and it tells me its correct! Otherwise, yes i would have done as you said.
     
  5. May 18, 2010 #4
    So, I guess this issue is resolved.
     
  6. May 18, 2010 #5
    No its not, my question is why is this integral equal to the quoted answer. I gave my attempt at the answer, which is nothing like the actual answer. Im baffled.
     
  7. May 18, 2010 #6
    Oh, so you want to calculate the integral.

    Try the substitution [itex]x = z \, \tan(p)[/itex].
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook